Check for mould in your house! I kept getting sick one winter and it turned out it was the mould.

Other than that, squeeze garlic into raspberry tea. For some reason that combination accelerates my healing when I'm already sick.

"I think the basic anti-aging diet is also the best diet for prevention and treatment of diabetes, scleroderma, and the various "connective tissue diseases." This would emphasize high protein, low unsaturated fats, low iron, and high antioxidant consumption, with a moderate or low starch consumption.

In practice, this means that a major part of the diet should be milk, cheese, eggs, shellfish, fruits and coconut oil, with vitamin E and salt as the safest supplements."

I was like that too 2 years ago. Constantly got sick, cold after cold after flue. Switching first to low-carb then really quick to Primal did help a bit with energy levels, but not entirely. What really did the trick for me was
1. Taking a magnesium supplement (I have to add not all of them are created equal, and for me the only one that works is the one people claim is least good) and variating with the levels (I take it before bed, sometimes more sometimes less, never the same levels for more than a week)
2. Cod liver oil. It has vitamin A, D (the version I take also has) K, and nice anti-inflammatory omega 3.
I still get 1 cold per year, but never more. My teeth have become perfect, my gums too, and except now that I'm pregnant and my body's acting all funny, my energy levels have been amazing.

I haven't gotten a cold since December 2012, when I started eating liver and bone broth. Added vitamin K and iodine supplements a month or two later. I have also never had a day when my legs dragged since these changes were made. I can't pinpoint one change as the key. I will just keep doing them all.